Microfilaments provide cells with motor function; in other words, they allow cells to move or change shape, or otherwise manipulate the environment around them. They are present in nearly all eukaryotic cells.
Structure
Microfilaments are comprised primarily of strands of actin, a globular protein, which is then wound into two strands twisted around one another into a thicker strand measuring roughly 7nm along their cross-sectional diameter.
Primary Uses
Within a cell, particularly in muscle cells, microfilaments are usually arranged in parallel and react with the protein Myosin to cause contraction. Similarly, they can be used in other cells to alter their shape to better suite their function; they can even be used to split a cell in two by pinching the center of a cell.
Microfilaments can also be used as small support structures, forming the backbone of such structures as microvilli, which project from a cell's plasma membrane to increase cell surface area, which in turn aids in the transfer of materials across the membrane. This function is usually found in special cells such as the nutrient-absorbing cells which line the walls of the intestine.
In plant cells, similar protrusions exist on the inside of the cell to circulate cytoplasm. This helps the transfer of nutrients and materials from cell to cell.
Recent Research
In 2003, experiments were conducted to find out whether mammalian Actin is able to be incorporated into the microfilament structure of plant cells. The experiments found that the rabbit actin became concentrated in and around the cell's nucleus, but did not form filamental structures and was not incorporated into the prevalnt microfilament structures found along the plant cell's walls.
Cytoskeleton: Microfilaments
Introduction
Microfilaments provide cells with motor function; in other words, they allow cells to move or change shape, or otherwise manipulate the environment around them. They are present in nearly all eukaryotic cells.Structure
Microfilaments are comprised primarily of strands of actin, a globular protein, which is then wound into two strands twisted around one another into a thicker strand measuring roughly 7nm along their cross-sectional diameter.Primary Uses
Within a cell, particularly in muscle cells, microfilaments are usually arranged in parallel and react with the protein Myosin to cause contraction. Similarly, they can be used in other cells to alter their shape to better suite their function; they can even be used to split a cell in two by pinching the center of a cell.Microfilaments can also be used as small support structures, forming the backbone of such structures as microvilli, which project from a cell's plasma membrane to increase cell surface area, which in turn aids in the transfer of materials across the membrane. This function is usually found in special cells such as the nutrient-absorbing cells which line the walls of the intestine.
In plant cells, similar protrusions exist on the inside of the cell to circulate cytoplasm. This helps the transfer of nutrients and materials from cell to cell.
Recent Research
In 2003, experiments were conducted to find out whether mammalian Actin is able to be incorporated into the microfilament structure of plant cells. The experiments found that the rabbit actin became concentrated in and around the cell's nucleus, but did not form filamental structures and was not incorporated into the prevalnt microfilament structures found along the plant cell's walls.Sources
Campbell, Neil, et.al. "Biology." (college text). 1986."Biology: Concepts and Connections." 2006.
Paves, Heiti; Truves, Erkki. "Incorporation of mammalian actin into microfilaments in plant cell nucleus." 2004. http://www.biomedcentral.com/1471-2229/4/7
Images from Molecular Expressions. http://micro.magnet.fsu.edu/cells/microfilaments/microfilaments.html